(1) Field of the Invention
The present invention relates to an automated apparatus enabling control of treatment of biological (sewage) sludge with a liquid base, such as lime, to render the sludge microbially inactive. In particular, the present invention relates to an apparatus which provides for flushing maintenance of the conduits supplying the lime and/or sludge to a holding tank.
(2) Description of Related Art
The general state of the art is set forth in U.S. Pat. No. 1,956,420 to Gleason et al, 2,129,267 to Fischer. U.S. Pat. Nos. 4,781,842 and 4,902,431 to Nicholson et al (which contain an extensive discussion of U.S. regulations for sludge treatment); U.S. Pat. No. 4,852,269 to Glorioso, U.S. Pat. Nos. 5,013,458, 5,186,840, 5,229,011 and 5,851,404 to Christy et al, U.S. Pat. Nos. 5,603,842, 5,716,518 to Whitaker et al, U.S. Pat. No. 5,679,262 to Girovich et al, U.S. Pat. No. 5,681,481 to Christy et al and U.S. Pat. No. 5,853,450 to Burnham et al.
The goal of these processes is to produce a Class A treated sludge (formerly PFRP) according to U.S. Environmental Protection Agency Rules. However, none of the prior art addresses the difficulties in maintaining such systems so that they perform routinely to these standards.
It is therefore an object of the present invention to provide an automated system or apparatus and method which continuously maintains the apparatus for the base treatment of sludge. In particular, it is an object of the present invention to provide for automated flushing of conduits which deliver sludge and other bases to holding tanks for treatment of the sludge. It is also an object of the present invention to provide an apparatus and method for the use thereof which is relatively inexpensive and reliable. These and other objects will become increasingly apparent by reference to the following description and the drawings.
The present invention relates to an apparatus for introducing a mixed liquid base in a first container into a biological sludge in a second container in fluid connection with the first container which comprises: a first conduit which extends into a bottom portion of the first container for removing the liquid base from the first container; pump means connected to the first conduit for pumping the liquid base from the first container; a second conduit connected to the first conduit through the pump for introducing the liquid base and sludge into the second container; flush conduits connected to the first and second conduits which can be connected to a source of water to intermittently flush the first and second conduits and the pump; electric valve means in the first conduit and second conduit and flush conduits for allowing the liquid base to flow from the first container to the second container and alternately to allow flushing of the first and second conduits and pump to remove retained amounts of the liquid base; and electric control means for controlling the valve means.
The present invention also relates to an apparatus for introducing a mixed liquid base in a first closed container into a biological sludge in a second closed container in fluid connection with the first container to achieve a pH of 12 or above in the sludge for two (2) hours or more which comprises: a first conduit which extends into a bottom portion of the first closed container for removing the liquid base from the first container; pump means connected to the first conduit for pumping the liquid base from the first container; a second conduit connected to the first conduit through the pump for introducing the liquid base separately into the second container; a third conduit connected to the second conduit for conveying the liquid base into a fourth conduit containing the sludge which is mixed with the liquid base and then fed into the second container; fifth, sixth and seventh conduits for providing water to the second conduit for flushing the second, third and fourth conduits and the pump respectively; electric valve means in the first, second, third, fourth, fifth and sixth conduits; and electric control means connected to the valve means, wherein the valve means allow pumping of the liquid base by the pump means from the first container through the first, second, third and fourth conduits directly into the second container to be mixed with the sludge and allow intermittent flushing of the first, second, third and fourth conduits with water to prevent caking of retained amounts of the base in the first to fourth conduits.
Further the present invention relates to a lime injector apparatus for introducing a mixed liquid lime from a first container into a biological sludge in a second closed container in fluid connection with the first container to provide a pH of 12 or above in the sludge which comprises: a first closed container for holding the liquid lime prior to introduction into the sludge for two (2) hours or more in the second closed container; a first conduit for removal of liquid lime from the first closed container; a progressive cavity pump connected to the first conduit outside of the first closed container for pumping the liquid lime into the second closed container; first valve means in the first conduit for directing the liquid lime through the pump; second valve means in a second conduit leading to the second closed container from the first conduit; minimum and maximum level sensing means in the first closed container; flush lines leading to the first and second conduits for introducing the water into the first and second conduits and pump to intermittently flush retained amounts of the liquid lime; and control means for remotely selectively operating the pump, the first valve and the second valve, wherein the liquid level in the first container is periodically at between the maximum level in the first container and refilled at the minimum level and wherein periodically the liquid lime is introduced into the second container.
Still further, the present invention relates to a method for providing a base in a biological sludge which comprises: providing an apparatus for including the base from a first container into the sludge in a second container which comprises: a first conduit which extends into a bottom portion of the first container for removing the liquid base from the first container; pump means connected to the first conduit for pumping the liquid base from the first container; a second conduit connected to the first conduit through the pump for introducing the liquid base and sludge into the second container; flush conduits connected to the first and second conduits which can be connected to a source of water to intermittently flush the first and second conduits and the pump; electric valve means in the first conduit and second conduit and flush conduits for allowing the liquid base to flow from the first container to the second container and alternately to allow flushing of the first and second conduits and pump to remove retained amounts of the liquid base; and electric control means for controlling the valve means; intermittently introducing the lime into the sludge in the second container and holding the sludge; and intermittently flushing the first and second conduits and the pump to remove the base.